Yong-Sil Lee

Total Synthesis of (+)-Brefeldin A

(+)-Brefeldin A was synthesized through an efficient route, which features (1) construction of the five-membered ring from a Crimmins aldol via tandem Li-I exchange and carbanion-mediated cyclization with concurrent removal of the chiral auxiliary, (2) introduction of the lower side chain (C10 to C16) via a Rh-catalyzed Michael addition of a vinyl boronic acid, (3) stereoselective reduction of the C7 ketone with SmI2, and (4) a 2-methyl-6-nitrobenzoic anhydride-mediated (Shiina) lactonization.

First total synthesis and structural confirmation of fluvirucinine A2 via an iterative ring expansion strategy.

The first asymmetric total synthesis of fluvirucinine A(2) has been accomplished. A key feature of the synthesis is an iterative lactam ring expansion to provide rapid access to the 14-membered lactam skeleton and three stereogenic centers. The excellent remote control of the three stereogenic centers relied on stereoselective amidoalkylation followed by an amide-enolate-induced aza-Claisen rearrangement. In addition, the structure of fluvirucinine A(2) has been completely elucidated by our total synthesis.

A versatile asymmetric synthesis of highly enantiomerically enriched 12(s)-HETE via a combination of enzymatic and chemical processes

This paper describes a versatile asymmetric synthesis of highly enantiomerically enriched 12(S)-HETE via enzymatic kinetic resolution of the key allylic alcohol synthon and the facile introduction of three alkyne units which were concomitantly converted to three alkenes units.

CoMFA and CoMSIA 3D QSAR Studies on Pimarane Cyclooxygenase-2 (COX-2)Inhibitors

Comparative molecular field analysis and comparative molecular similarity indices analysis were performed on twenty five analogues of pimarane COX-2 inhibitor to optimize their cyclooxygenase-2 (COX-2) selective anti-inflammatory activities.